A. Technical Field
The present invention relates to a process for producing a high molecular weight thermoplastic resin composition and its use, and more specifically, relates to: a process for producing a high molecular weight thermoplastic resin composition, which comprises the step of mixing a thermoplastic resin with a specific reforming additive to carry out a reaction therebetween; and uses of the resultant high molecular weight thermoplastic resin composition.
B. Background Art
It is generally known that it is possible to improve mechanical properties of a molded product comprising a thermoplastic resin by a process including the step of mixing the thermoplastic resin with a polyfunctional compound to carry out a reaction therebetween. Hereupon, the above polyfunctional compound is used to increase the molecular weight of the above thermoplastic resin by an addition reaction of the polyfunctional compound with a terminal group of the thermoplastic resin.
The above conventional process is especially effective in converting the thermoplastic resin into a high molecular weight one. For example, a process is reported, which comprises the step of mixing a polyester resin with an aromatic tetracarboxylic dianhydride in a melted state to carry out a reaction therebetween (e.g. JP-B-13860/1972).
In the above conventional process for the high molecular weight conversion, generally, pyromellitic dianhydride is preferably used as the aromatic tetracarboxylic dianhydride in view of such as reactivity and availability (JP-B-13860/1972, JP-A-507523/1993 and JP-B86518/1994). The high molecular weight conversion is effectively carried out by an addition reaction between the pyromellitic dianhydride and the thermoplastic resin.
However, indeed the increase of the molecular weight may be accomplished by the above conventional process, but this process might involve disadvantages in that the reproducibility of the intrinsic viscosity of the final product is poor, or in that gelation occurs in the reaction. Therefore, this conventional process is not what has sufficiently been established as a stable production process.
A. Object of the Invention
An object of the present invention is to provide a process for producing a high molecular weight thermoplastic resin composition, which can give the high molecular weight thermoplastic resin composition with good reproducibility and stably.
Another object of the present invention is to provide a molded structure, which is obtained from the high molecular weight thermoplastic resin composition obtained from the production process, as mentioned immediately above, and is excellent in the mechanical properties.
B. Disclosure of the Invention
The present inventor diligently studied to solve the above problems. As a result, he focused his attention on the chemical and physical properties of pyromellitic dianhydride used in the reaction, and then he found that the high molecular weight thermoplastic resin composition could be produced with good reproducibility and stably by a production process involving an addition reaction of a thermoplastic resin with pyromellitic dianhydride having specific particle forms (which are not conventional round or spherical ones, but, preferably, linear or needle-like ones, for example, as shown in FIG. 1) or specific physical properties.
Furthermore, the inventor found that because, as is stated above, the high molecular weight thermoplastic resin composition resultant from such a production process exhibited uniform physical properties, a molded structure obtained from this resin composition was excellent in the mechanical properties.
Thus, a process for producing a high molecular weight thermoplastic resin composition, according to the present invention, comprises the step of mixing a thermoplastic resin with pyromellitic dianhydride to carry out a reaction therebetween to convert the thermoplastic resin into a high molecular weight one, wherein the thermoplastic resin has a functional group reactable with pyromellitic dianhydride, and this process is characterized in that the pyromellitic dianhydride has intrinsically linear or needle-like particle forms.
In addition, another process for producing a high molecular weight thermoplastic resin composition, according to the present invention, comprises the step of mixing a thermoplastic resin with pyromellitic dianhydride to carry out a reaction therebetween to convert the thermoplastic resin into a high molecular weight one, wherein the thermoplastic resin has a functional group reactable with pyromellitic dianhydride, and this process is characterized in that the pyromellitic dianhydride has particle forms which are characterized by exhibiting a bulk density of 0.4xcx9c0.9 g/ml.
In addition, yet another process for producing a high molecular weight thermoplastic resin composition, according to the present invention, comprises the step of mixing a thermoplastic resin with pyromellitic dianhydride to carry out a reaction therebetween to convert the thermoplastic resin into a high molecular weight one, wherein the thermoplastic resin has a functional group reactable with pyromellitic dianhydride, and this process is characterized in that the pyromellitic dianhydride has particle forms which are characterized by exhibiting a rest angle of 50xcx9c70 degrees.
A high molecular weight thermoplastic resin composition, according to the present invention, is characterized by being obtained by any one of the above production processes according to the present invention.
In addition, a molded structure, according to the present invention, is characterized by being obtained by a process including the step of melt-molding the above high molecular weight thermoplastic resin composition according to the present invention.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.